Since identifying the gap in the market, the psychologist and graphic designer have set about creating a series of thoughtful and supportive get-well cards for friends, family and colleagues affected by mental illness.

Statistics reveal that approximately one in every five Australians will experience some form of mental disorder but Sam Booker said when a friend was affected, she had been unable to find an appropriate card to send.

"I first had the idea a couple of years ago in response to a friend of mine. Her son had attempted suicide," she said.

"I was working as a psychologist at the time but I didn't really know what to do as a friend.

"And I thought well why doesn't Hallmark make cards for this sort of thing? And that's how the idea came about."

Hope Street Cards are tailored to specific diagnoses and conditions, such as depression and anxiety while there are more general cards appropriate for all psychiatric conditions.

While researching the idea, Ms Booker said the only mental health get-well cards on the market were e-cards.

She said she had been "gobsmacked" by the inappropriate nature of some, including one card with a picture of a sticky tape dispenser and the words 'put yourself back together'.

Ms Booker acknowledged it can be difficult for people to know what's appropriate to say in some situations and that's why the Booker sisters' Hope Street Cards include information on mental illnesses and suggestions on how best to support that person.

"For me, I find it easier to write the text for the cards because I've worked as a psychologist for a long time and I've had my own experience with mental illness too," Ms Booker said.

The Bangalow-based Hope Street Cards will be launched in Ballina on October 6. A $1 donation from each card sold will go to the Black Dog Institute.

1 in 5 Aussies will experience some form of mental illness each year

1 in 4 people who have experiences mental health issues have received a card but 4 out of 5 say a card would be a good way for others to let them know they are thinking of them.

Studies have shown that psychiatric inpatients receive about half as many cards and gifts as medical inpatients.